2001 TJ sputtering issue (New fuel pump?)

Bushwacked

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Aug 31, 2020
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Colorado
A little back story on my jeeps symptoms my jeep has 232,793 miles and a rebuild head last year with all new O2 sensors, My CPS was replaced right around the same time.
All issues only have happened in the morning in the cool air before the afternoon heat. until today. its a 2001 sport manual 6cyl.

So about 4 weeks ago while I was driving up a hill early in the morning by my house my jeep did a small Lurch or hesitation It happened a second time 2 days later and then that was it. At first I thought it was the clutch slipping. it hasn't happened on that hill again since. I had been having long starts in the morning after sitting over the weekend i thought maybe my battery was going out it was about 5-6 years old. So i replaced it. That's when the problems really started. a day or two after the battery swap my jeep would start to die while at idle at a light. so i started warming up the engine before i leave then it drives fine once its a operating temp. No codes saved or thrown. First I cleaned the AIC in case it was getting stuck. it still was happening. So i replaced the IAC not OEM yet they are on back order till the begging of 2022 according to WeRMopar. For more tests i replaced the MAP sensor, still died while idling, changed the temp sensor incase that was throwing a short. still same issue, then last but not least i changed the TPS still an issue. once the engine is at full temp it doesn't seem to happen. i was in a rush one morning and decided to take off without waiting for it to warm up all the way. while driving about 30mph slowing down for a red light it started sputtering and the power indicator dropped to zero and the gas gage dropped to zero right after that. I though OK finally something new maybe it was the alternator going out or shorting, I traced all the cables and shook and pulled on them while the engine was running nothing happened so I replaced the alternator as well. It seamed to drive without issue for a few days then while i was on the highway twice before the engine was at max temp i had 2 more quick lurches/Hesitations not on a hill but straight ground.

Forward to Today in the afternoon 95 degree i didn't not let the engine get to max temp before i left work because it hasn't been an issue. at the first stop light the engine started to sputter never fully died. I tried to give it gas but it kept sputtering and revved up and down between 0 and 750 rpms like its not getting fuel until the last second to stop it from dyeing completely i had to turn off the engine to get it to stop. took a couple tried to get it to start and it drove the rest of the way home fine still no codes.

So now I am thinking it may be the fuel pump going out since I still am still not getting any codes I have been chasing this ghost for the last few weeks.
I don't know if its relevant but the past 7 years my fuel gauge has been picky and will decide to drop to zero for no reason. but no other issues than that.

I am looking at the Carter P75045M Fuel Pump Module Assembly since I cant seem to find any Bosch. Any other suggestions for the assembly for an 01

Fuel tank question.
While I was researching fuel pumps I saw some were listed as 15gal or 19gal only according to my VIN check i should have 19gal tank but if i go by the tank gauge and fill when almost at empty I have never been able to add more than 14-15 gals, any ideas to that?

 
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The proper fuel pump for the '01 4.0L is a 67655 which does show up on Amazon from time to time...
During the last appearance I purchased a spare for my Jeep.
I have heard that some members recommend the Delphi fuel pump...
Other members may have different experiences and suggestions...

What is the maker of the O2 sensors there were installed last year ?
NTK/NGK are the recommended manufacturer...
 
The proper fuel pump for the '01 4.0L is a 67655 which does show up on Amazon from time to time...
During the last appearance I purchased a spare for my Jeep.
I have heard that some members recommend the Delphi fuel pump...
Other members may have different experiences and suggestions...

What is the maker of the O2 sensors there were installed last year ?
NTK/NGK are the recommended manufacturer...
Used the NTK O2 Sensors

NTK.webp
 
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Before you go throwing a fuel pump at it, you need to confirm it's actually dropping fuel pressure.
Fuel pumps usually start acting up once they get hot. Put a gauge on it and verify.

Your jeep is a 2001 with 230k miles on it. Check your grounds. There are several on the engine block itself. Make sure they are not rusted and corroded. A poor ground will wreak havok.
Check the connector at the firewall behind the valve cover verify there is no corrosion at the terminals. Also check the harness in that area for any bare/exposed/corroded wiring that could be causing an issue.
Check the injector harness itelf. check the harness going to the crank sensor.
These are all known issues with our TJ's

Go to the TJ Resourses section of the forum and look at the 2001 TJ service manual. go to the wire schematics to find the ground locations. Check the engine and pcm grounds.
 
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Do check your fuel pressure, though it may not be easy if your 2001 doesn't have the Shrader valve on the fuel rail as later models did not. My '97 did have one. If present, the Shrader valve looks like an oversize tire valve stem and it has a protective black plastic screw cap over the top of it.

So far as your gas tank capacity goes, very few TJs came with the smaller 15 gallon tank. And many with the 19 gallon tank refuse to believe it's a 19 gallon tank because it never takes more than 12-14 gallons to fill up. That's only because the gas gauge is notoriously inaccurate. I never refill my gas tank until the gauge indicator is on the Empty mark or close to it and even then it seldom take more than 16-17 gallons. It has to be well below that before it even approaches taking 18 gallons at the gas pump.
 
OK so here is video of the gauge this morning before work. The first stutter you can hear at about 22 seconds i set the phone down to grab my flashlight from the front seat. Second minor stutter around 49 seconds then the engine stutters and dies at the 3min mark.

The second video is the last but biggest stutter engine does not die though. 6second - 22 seconds

Drove to work fine after this.
 
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I'm going to be honest and say I don't think it's the fuel pump. It momentarily drops pressure but recovers, almost like its loosing power or ground.
again like I said I would check your grounds, connectors and the wiring harness.

Also when your jeep dies @ the 3 minute mark, you are not dropping fuel preasure.
 
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Inspect ground g105, it should be on the right side of the engine block. There are multiple wires going to it. make sure it is not corroded and rusty. inspect the wires for corrosion. clean if necessary.

Inspect the connectors at the pcm, make sure there is no terminal fretting/corrosion or water intrusion. apply some dielectric grease to the terminals before reconnecting.

If you have access to a scanner that reads live data, watch the crank/cam rpm's during a cold start to see if one drops out.
 
I also did a general Pressure test and turned the key on it goes up to 50 and within a couple minutes the pressure drops down to 20 with the key in the On position. It should stay pressurized with the key on correct? I will start checking grounds tonight.
 
I also did a general Pressure test and turned the key on it goes up to 50 and within a couple minutes the pressure drops down to 20 with the key in the On position. It should stay pressurized with the key on correct? I will start checking grounds tonight.
IF you are testing the fuel pressure by turning the ignition to ON; the fuel pump will only run 3-5 seconds and shut off unless the engine is running. IF the system pressure drops to 20 psi after the pump shuts off; then that indicates the check valve is not holding pressure.
 
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I also did a general Pressure test and turned the key on it goes up to 50 and within a couple minutes the pressure drops down to 20 with the key in the On position. It should stay pressurized with the key on correct? I will start checking grounds tonight.
Key on you should get an initial pressure reading of 49psi +/- 5psi. The fuel pump runs for approx 3 seconds when turning the key to the run position.
you want to make sure that the system does not drop below 30psi within the first 5 minutes.
 
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when was the last time you changed the spark plugs/wires/distributor cap and rotor/ignition coil?
 
I forgot I had doctor appointment's yesterday so I have not got a chance to check the grounds but this morning I held the rpms at around 1200 and the engine never tired to sputter or die, while warming up. I don't know if this is helpful or gives any of you other thoughts. Once it was warmed up I ran inside to grab my work bag and I heard the engine rpm drop for a second and back to normal idle.
 
I have checked the grounds and cleaned them. i do not have a live scanner. I am about to take it to a mechanic.
Does anyone think a failing fuel pump relay could be behind all this?